As progress evolves in the control of a cursor through a display interface of a computer a number of considerations are operating to make accuracy in positioning and in turn user efficiency, increasingly difficult to achieve. In the art, a positioning device called a mouse has evolved that fits in the hand of the user and which has a rotatable element on the under side that rotates against the surface on which the mouse rests when the mouse is moved. The mouse internally has circuitry that provides and transmits signals correlated with the rotatable element movement that results in movement of the cursor or pointer on the display screen.
Switching elements that deliver operating system signals through the mouse-display interface can impose psychomotor limitations for a user. The switches are positioned to be under an adjacent finger when the mouse is in the hand of the user but the actuation force for each switch by the respective finger has force components in more than one direction that can introduce a movement force on the mouse that may disrupt the position of the mouse and in turn the cursor. Other users may have other types of hand coordination problems, making it difficult for them to reach and retain targeted locations with a mouse. Complexity is further added by operating system requirements for such actuation features as “double clicks”. Complexity is still further added by the fact that some users as their experience and skills change could benefit by having some adjustability in the movement response of the mouse.
Operating system controls that are installed to introduce system biases favoring a particular user such as are discussed in U.S. Pat. No. 5,642,131 also recognize that accurate cursor positioning directly to a particular desired location is inefficient because when the user is able to position the cursor close to the desired location overshoot and undershoot make precise positioning of the cursor difficult. Maneuvering the cursor directly to the desired location must be done with care, requiring slower action, which in turn affects productivity and efficiency.